#3 of 7 in Antivirus software
Microsoft Defender review
The antivirus built into Windows, switched on by default at no extra cost. It is regularly tested by independent labs and is a solid baseline for many home users.
Last checked · Available: Global (built into Windows)
8.1/10, Very good
5 criteria
Strongest on value for money (10.0).
See every score and reasonScorecard
How Microsoft Defender scores
Tested in AV-TEST and AV-Comparatives series with generally good results.
Lab reports have shown more slowdown in some tasks than the lightest rivals.
No extra cost on Windows.
Core protection and firewall; few consumer extras.
On by default with nothing to install, but Windows only.
Best for
Windows users who want solid no-cost protection.
Not ideal for
People who want extras such as a VPN or identity monitoring.
Trade-offs
Pros and cons
What stands out
- No extra cost
- Enabled by default
- Tested by major independent labs
Worth knowing
- Windows only
- Few extras beyond core protection
At a glance
Key facts and pricing
- Free version
- Yes
- Money-back window
- Not published
- Free trial
- Not published
- In AV-TEST or AV-Comparatives tests
- Yes
- Main platforms
- Windows (built in)
- Company base
- United States
- Price band
- Budget
- Based in
- United States
Pricing: Included with Windows at no extra cost. Free plan: yes (built in).
Head to head
Compare Microsoft Defender with
Also consider
Microsoft Defender alternatives
Questions
Microsoft Defender: common questions
Is Microsoft Defender good?
Microsoft Defender scores 8.1 out of 10 in our antivirus software scorecard, rank 3 of 7. The antivirus built into Windows, switched on by default at no extra cost. It is regularly tested by independent labs and is a solid baseline for many home users.
Who is Microsoft Defender best for?
Best for windows users who want solid no-cost protection. Less suited to people who want extras such as a VPN or identity monitoring.
How much does Microsoft Defender cost?
Included with Windows at no extra cost. Free plan: yes (built in).
What are Microsoft Defender's key terms and features?
Free version: Yes; In AV-TEST or AV-Comparatives tests: Yes; Main platforms: Windows (built in); Company base: United States. As published by the brand, last checked 2026-11-01.
What is a good alternative to Microsoft Defender?
Bitdefender (8.7/10) is the top-scoring option in the same list. See the full antivirus software ranking for every alternative.
Transparency
Sources and how we make money
Sources we used
Checked 1 Nov 2026. Brands change terms often; confirm on the brand's site before you buy.
How we make money
Some links to brands may earn AltFTool a commission. That never changes a score, a rank or whether a brand is listed. Scores come only from the criteria above.
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